feat: replace clsx with cn util

src/shared/ui/PerspectivePlan/PerspectivePlan.svelte

@@ -5,7 +5,7 @@
 -->
 <script lang="ts">
 import type { PerspectiveManager } from '$shared/lib';
-import clsx from 'clsx';
+import { cn } from '$shared/lib';
 import { type Snippet } from 'svelte';
 
 interface Props {
@@ -73,7 +73,7 @@ const isVisible = $derived(manager.isFront);
 </script>
 
 <div
-    class={clsx('will-change-transform', className)}
+    class={cn('will-change-transform', className)}
     style:transform-style="preserve-3d"
     style:transform={style?.transform}
     style:filter={style?.filter}